METHOD FOR IMPROVING QUALITY AND FUNCTIONALITY OF FILTER PAPER SUITABLE FOR COLLECTING BIOLOGICAL SAMPLES

Description

Field of the invention

[0001] The invention relates to a method for diminishing variation between results analyzed from sheets of filter paper each being impregnated with at least one sample of biological material.

Background

[0002] A conventional practice is to impregnate one or more sample drops of biological material to be examined into a sheet of filter paper, dry the sheet of filter paper impregnated with the biological material, and then send the sheet of filter paper to a laboratory for examination. The biological material to be examined can be, for example, blood of a newborn baby. In the laboratory, one or more sample disks containing the biological material to be examined are cut or punched out from the sheet of filter paper and then the one or more sample disks that have been cut or punched are subjected to analysis. It has, however, turned out that properties of the filter paper may vary between filter papers. In some cases, these property variations may result in variation between measurement results obtained from sheets of filter paper impregnated with same biological material. Figure 1 shows a histogram of results measured in an example case in which blood was impregnated into seven different sheets of filter paper from different filter paper batches. The analyte was measured by eluting the blood from the sample disk punched out from the filter paper impregnated with blood and by assaying the analyte. The results were obtained by measuring fluorescence. The vertical axis of the histogram shown in figure 1 is the count number obtained with the photo detector. The count number is inversely proportional to the activity of analyte. In this example case, the analyte that is measured is biotinidase which is an enzyme that catalyses the cleavage of biotin, vitamin H, from small biotinylated peptides and biocytin, thus, recycling the vitamin. The reaction is hydrolytic, in which the substrate, i.e. the molecules at the beginning of the reaction, is converted to the products of the reaction. For example, biocytin can be converted to biotin and lysine. Biotinidase can also catalyze the cleavage of synthetic substrates that release a fluorescent dye, such as biotin-6-aminoquinoline, for screening of newborns for biotinidase deficiency. Enzyme activity is defined as the moles of substrate converted per unit time. Enzyme activity is a measure of the quantity of active enzyme present and is hence dependent on conditions, which should be specified. The SI unit is the katal, 1 katal = 1 mol s^-1. A more practical and commonly used value is enzyme unit, 1 (U) = 1 µmol min^-1. 1 U corresponds to 16.67 nanokatals. As can be seen from figure 1, there is, in this exemplifying case, relatively strong variation between results obtained with the different sheets S1-S7 of filter paper.

[0003] US 5719035 A discloses a method for analysing disks punched from dried blood spots impregnated a filter paper.

[0004] An inconvenience related to the above described phenomenon is that it may cause additional work and additional requirements to personnel collecting the samples of biological material, to personnel performing the measurements in laboratories, and also to specialists interpreting the analysis results.

Summary

[0005] In accordance with the invention, there is provided a method for treating sheets of filter paper and for measuring an analyte from a biological material impregnated into said sheets of filter paper, the method comprising:

• subjecting the sheets of filter paper to gaseous substance containing at least 30 grams water per cubic meter, and/or
• wetting the sheets of filter paper with water and subsequently drying the sheet of filter paper

so as to diminish the variation in measurements of an analyte from a biological material impregnated into the sheets of filter paper, wherein the method further comprising:

• subsequently impregnating at least one sample drop of biological material into each of the sheets of filter paper,
• drying the sheets of filter paper impregnated with the biological material,
• cutting or punching out from the dried sheets of filter paper at least one sample disk containing the biological material, and
• measuring the analyte quantitatively and/or qualitatively from the biological material impregnated into the sheets of filter paper.

[0006] The fact that the quality and properties of filter paper can be improved in the above-described ways has significance at least for the following groups: the producers of analytical methods, the manufacturers of filter paper, the manufacturers of measurement and analysis devices, personnel collecting samples, personnel performing laboratory analysis, and specialists interpreting the analysis results.

[0007] A number of exemplifying, i.e. non-limiting, embodiments of the invention are described in accompanied dependent claims.

[0008] Various exemplifying embodiments of the invention both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying embodiments when read in connection with the accompanying drawings.

[0009] The verbs "to comprise" and "to include" are used in this document as open limitations that neither exclude nor require the existence of unrecited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated.

Brief description of the figures

[0010] The exemplifying embodiments of the invention and their advantages are explained in greater detail below in the sense of examples and with reference to the accompanying drawings, in which:

figure 1 shows a histogram of results measured in an example case in which blood was impregnated into seven different sheets of filter paper from different filter paper batches,

figures 2a and 2b show flow charts of methods according to exemplifying embodiments of the invention for diminishing variation between and/or within individual sheets of filter paper which are suitable for collecting samples of biological material,

figures 3a and 3b show flow charts of methods according to exemplifying embodiments of the invention for handling biological material with the aid of filter paper, and

figure 4 shows a histogram of results measured in an example case in which blood was impregnated into seven different sheets of filter paper taken from the same filter paper batches as in the example case of figure 1 and furthermore treated with a method according to an exemplifying embodiment of the invention; for the purpose of comparison, figure 4 shows also the histogram of the results shown in figure 1.

[0011] Figure 1 was already explained in conjunction with the description of the related prior art in the "Background"-section of this document.

Description of the embodiments

[0012] Figure 2a shows a flow chart of a method according to an exemplifying embodiment of the invention for diminishing variation between and/or within individual sheets of filter paper which are suitable for collecting samples of biological material. The method comprises subjecting, in phase 201, the sheets of filter paper to gaseous substance containing at least 30 grams water per cubic meter. More preferably, the gaseous substance contains at least 40 grams water per cubic meter, and yet more preferably, the gaseous substance contains at least 50 grams water per cubic meter, and still more preferably, the gaseous substance contains at least 70 grams water per cubic meter. The gaseous substance can be, for example, moist air in which there is at least 30 grams water per cubic meter.

[0013] In a method according to an exemplifying embodiment of the invention, the sheets of filter paper are subjected to steam having temperature at least 100°C, or more advantageously at least 120°C. The sheets of filter paper may be subjected to the steam for a time period of e.g. at least 15 minutes.

[0014] Figure 2b shows a flow chart of a method according to another exemplifying embodiment of the invention for diminishing variation between and/or within individual sheets of filter paper which are suitable for collecting samples of biological material. The method comprises wetting, in phase 202, the sheets of filter paper with water and subsequently, in phase 203, drying the sheets of filter paper.

[0015] Figure 3a shows a flow chart of a method according to an exemplifying embodiment of the invention for handling biological material with the aid of filter paper. The method comprises subjecting, in phase 301, a sheet of filter paper to gaseous substance containing at least 30 grams water per cubic meter, and subsequently in phase 304, impregnating at least one sample of the biological material into the sheet of filter paper. The biological material can be, for example, blood.

[0016] Figure 3b shows a flow chart of a method according to another exemplifying embodiment of the invention for handling biological material with the aid of filter paper. The method comprises, in successive phases 302 and 303, wetting a sheet of filter paper with water and drying the sheet of filter paper, and subsequently in phase 304, impregnating at least one sample of the biological material into the sheet of filter paper.

[0017] A method according to an exemplifying embodiment of the invention further comprises measuring an analyte quantitatively and/or qualitatively from the biological material, e.g. blood, impregnated into the sheet of filter paper.

[0018] In a method according to an exemplifying embodiment of the invention, activity and/or concentration of the analyte is measured from the biological material, e.g. blood, impregnated into the sheet of filter paper.

[0019] In a method according to an exemplifying embodiment of the invention, the measuring of the analyte from the biological material, e.g. blood impregnated into the sheet of filter paper, is carried out as a fluorescence measurement. It should be, however, noted that methods according to various embodiments of the present invention are applicable also with various other measuring methods such as, for example, absorbance, time resolved fluorescence, luminescence, mass analysis.

[0020] A method according to an exemplifying embodiment of the invention comprises measuring activity of the biotinidase enzyme from blood impregnated into the sheet of filter paper.

[0021] Figure 4 shows a histogram 401 of results measured in an example case in which blood was impregnated into seven different sheets ST1-ST7 of filter paper that had been treated with a method according to an exemplifying embodiment of the invention. In this exemplifying case, the treatment was autoclavation, i.e. subjection the sheets ST1-ST7 of filter paper to high pressure saturated steam at 120°C or more for a time period of typically 15-20 minutes. The sheets ST1-ST7 of filter paper have been taken from the same filter paper batches as the untreated sheets S1-S7 of filter paper used in the example case illustrated in figure 1. For the purpose of comparison, figure 4 shows also the histogram 402 of results that are shown in figure 1 and that relate to the corresponding untreated sheets S1-S7 of filter paper. The vertical axis of the histograms 401 and 402 shown in figure 4 is the count number obtained with a photo detector. The count number is inversely proportional to the activity of the analyte that is measured. In this example case, the analyte that is measured is biotinidase.

Claims

1. A method for treating sheets of filter paper and for measuring an analyte from a biological material impregnated into said sheets of filter paper, the method comprising:

- subjecting (201, 301) the sheets of filter paper to gaseous substance containing at least 30 grams water per cubic meter, and/or

- wetting (202, 302) the sheets of filter paper with water and subsequently drying (203, 303) the sheet of filter paper

so as to diminish the variation in measurements of an analyte from a biological material impregnated into the sheets of filter paper, wherein the method further comprising:

- subsequently impregnating at least one sample drop of biological material into each of the sheets of filter paper,

- drying the sheets of filter paper impregnated with the biological material,

- cutting or punching out from the dried sheets of filter paper at least one sample disk containing the biological material, and

- measuring the analyte quantitatively and/or qualitatively from the biological material impregnated into the sheets of filter paper.

2. A method according to claim 1, wherein the gaseous substance is moist air in which there is at least 30 grams water per cubic meter.

3. A method according to claim 1, wherein the sheets of filter paper are subjected to steam having temperature at least 100°C.

4. A method according to claim 3, wherein the temperature of the steam is at least 120°C.

5. A method according to claim 3 or 4, wherein the sheets of filter paper are subjected to the steam for a time period of at least 15 minutes.

6. A method according to any of claims 1-5, wherein the biological material is blood.

7. A method according to claim 1, wherein the measuring is carried out as one of the following: a fluorescence measurement, an absorbance measurement, a time resolved fluorescence measurement, a luminescence measurement, a mass analysis measurement.

8. A method according to claim 6, wherein activity and/or concentration of the analyte is measured from the blood impregnated into the sheets of filter paper.

9. A method according to claim 7, wherein the measuring is carried out as a fluorescence measurement.

10. A method according to claim 6, wherein the method comprises measuring activity of the biotinidase enzyme from the blood impregnated into the sheets of filter paper.

Ansprüche

1. Verfahren zum Behandeln von Filterpapierblättern und zum Messen eines Analyten aus einem biologischen Material, das in die Filterpapierblätter imprägniert ist, wobei das Verfahren Folgendes umfasst:

- Aussetzen (201, 301) der Filterpapierblätter einer gasförmigen Substanz, die mindestens 30 Gramm Wasser pro Kubikmeter enthält, und/oder

- Benetzen (202, 302) der Filterpapierblätter mit Wasser und anschließendes Trocknen (203, 303) der Filterpapierblätter,

um die Schwankung der Messungen eines Analyten aus einem biologischen Material, mit dem die Filterpapierblätter imprägniert sind, zu verringern, wobei das Verfahren ferner Folgendes umfasst:

- anschließendes Imprägnieren mindestens eines Probetropfens biologischen Materials in jedes der Filterpapierblätter,

- Trocknen der mit dem biologischen Material imprägnierten Filterpapierblätter,

- Ausschneiden oder Ausstanzen mindestens einer das biologische Material enthaltenden Probenscheibe aus den getrockneten Filterpapierblättern, und

- Quantitatives und/oder qualitatives Messen des Analyten aus dem biologischen Material, mit dem die Filterpapierblätter imprägniert sind.

2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die gasförmige Substanz feuchte Luft ist, in der mindestens 30 Gramm Wasser pro Kubikmeter enthalten sind.

3. Verfahren nach Anspruch 1, wobei die Filterpapierblätter Dampf mit einer Temperatur von mindestens 100°C ausgesetzt werden.

4. Verfahren nach Anspruch 3, wobei die Temperatur des Dampfes mindestens 120°C beträgt.

5. Verfahren nach Anspruch 3 oder 4, wobei die Filterpapierblätter dem Dampf für eine Zeitdauer von mindestens 15 Minuten ausgesetzt werden.

6. Verfahren nach einem der Ansprüche 1 bis 5, wobei das biologische Material Blut ist.

7. Verfahren nach Anspruch 1, wobei die Messung als eine der folgenden durchgeführt wird: eine Fluoreszenzmessung, eine Extinktionsmessung, eine zeitaufgelöste Fluoreszenzmessung, eine Lumineszenzmessung, eine Massenanalysemessung.

8. Verfahren nach Anspruch 6, wobei die Aktivität und/oder Konzentration des Analyten aus dem Blut gemessen wird, mit dem die Filterpapierblätter imprägniert sind.

9. Verfahren nach Anspruch 7, wobei die Messung als Fluoreszenzmessung durchgeführt wird.

10. Verfahren nach Anspruch 6, wobei das Verfahren das Messen der Aktivität des Biotinidase-Enzyms aus dem Blut umfasst, mit dem die Filterpapierblätter imprägniert sind.

Revendications

1. Procédé de traitement de feuilles de papier filtre et de mesure d'un analyte à partir d'un matériau biologique imprégné dans lesdites feuilles de papier filtre, le procédé comprenant :

- la soumission (201, 301) des feuilles de papier filtre à une substance gazeuse contenant au moins 30 grammes d'eau par mètre cube, et/ou

- le mouillage (202, 302) des feuilles de papier filtre avec de l'eau et ensuite le séchage (203, 303) de la feuille de papier filtre de manière à diminuer la variation des mesures d'un analyte à partir d'un matériau biologique imprégné dans les feuilles de papier filtre, dans lequel le procédé comprenant en outre :

- l'imprégnation ultérieure d'au moins une goutte échantillon de matériau biologique dans chacune des feuilles de papier filtre,

- le séchage des feuilles de papier filtre imprégnées du matériau biologique,

- le découpage ou poinçonnage à partir des feuilles séchées de papier filtre d'au moins un disque échantillon contenant le matériau biologique, et

- la mesure quantitative et/ou qualitative de l'analyte à partir du matériau biologique imprégné dans les feuilles de papier filtre.

2. Procédé selon la revendication 1, dans lequel la substance gazeuse est de l'air humide dans lequel il y a au moins 30 grammes d'eau par mètre cube.

3. Procédé selon la revendication 1, dans lequel les feuilles de papier filtre sont soumises à de la vapeur ayant une température d'au moins 100 °C.

4. Procédé selon la revendication 3, dans lequel la température de la vapeur est d'au moins 120 °C.

5. Procédé selon la revendication 3 ou 4, dans lequel les feuilles de papier filtre sont soumises à la vapeur pendant une durée d'au moins 15 minutes.

6. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel le matériau biologique est du sang.

7. Procédé selon la revendication 1, dans lequel la mesure est effectuée comme l'une des suivantes : une mesure de fluorescence, une mesure d'absorbance, une mesure de fluorescence résolue en temps, une mesure de luminescence, une mesure d'analyse de masse.

8. Procédé selon la revendication 6, dans lequel l'activité et/ou la concentration de l'analyte est mesurée à partir du sang imprégné dans les feuilles de papier filtre.

9. Procédé selon la revendication 7, dans lequel la mesure est effectuée comme une mesure de fluorescence.

10. Procédé selon la revendication 6, dans lequel le procédé comprend la mesure de l'activité de l'enzyme biotinidase à partir du sang imprégné dans les feuilles de papier filtre.

Drawing